Good idea! Actually, I already have data for yoga in my database - I just didn't add it because I wasn't sure if it's possible to generate random yoga workouts or if they need to follow an order to make sense
I'm sure a lot of yoga instructors would cringe at this comment. Yoga routines generally start out with same few basic warm up moves, they generally focus on a particular area of the body, working up to more difficult poses as the routine goes on, and end with some lighter stretching to cool off, most typically finishing with savasana (aka lying down on your back).
You could probably algorithmically generate routines like this, but I wouldn't suggest a randomly generated one for best results (or safety). There's a few really good instructors on YouTube, and I'd personally recommend looking there if you're after a thoughtfully composed routine to follow.
The site is missing warmups in general, and would be a good addition. Perhaps there some warmups would only be for specific exercise types. E.g. yoga warmups for yoga moves.
It would be great if a yoga mat were another option. Then you could link to videos of yoga moves, just as you do with other exercises.